KR101153625B1 - Method for manufacturing electrode for for secondary power and method for manufacturing secondary power using thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing a secondary power electrode and a secondary power source, the method for manufacturing a secondary power electrode according to an embodiment of the present invention comprises the steps of forming an electrode material on a conductive sheet; Depositing lithium on the electrode material to form a lithium thin film layer; Doping the deposited lithium onto the electrode material; And adjusting the doping level by monitoring the doping amount of lithium. According to the present invention, lithium ions may be doped into the cathode before the cells are assembled, thereby simplifying the manufacturing process, improving the doping rate of the lithium ions and making the doping amount uniform.

Description

Electrode manufacturing method for secondary power supply and secondary power supply manufacturing method using the same {METHOD FOR MANUFACTURING ELECTRODE FOR FOR SECONDARY POWER AND METHOD FOR MANUFACTURING SECONDARY POWER USING THEREOF}

The present invention relates to a method for manufacturing a secondary power electrode and a method for manufacturing a secondary power source using the same, and more particularly, to a method for manufacturing a secondary power electrode that can be manufactured by a simple method by improving the doping rate of lithium ions.

With the development of electric vehicles (EVs) or hybrid vehicles (HEVs) with engines and motors, new methods for improving fuel economy have been developed, with new energy storage devices that can meet energy capacity and output. Particularly referred to as energy storage devices for electric vehicles or hybrid vehicles today, there are secondary power sources (Ni-MH battery, Li-ion battery (LiB), etc.) and electrochemical capacitors (supercapacitors).

Secondary power sources, such as lithium ion batteries, are typical energy storage devices with high energy density. However, secondary power supplies have limited output characteristics compared to supercapacitors. In contrast, supercapacitors are high power storage devices, but have a lower energy density than lithium ion batteries. To overcome each of these drawbacks, Li pre-doping technology has been devised. Supercapacitors, already known as Li-ion capacitors (LiCs), are already commercialized, and lithium-ion capacitors improve the energy density of conventional electric double layer capacitor (EDLC) type supercapacitors by three to four times. have. The use of such supercapacitors has been recently applied or reviewed as a power source for heavy-duty equipment such as solar and solar power generation, wind power generation, construction equipment such as excavators, as well as energy storage for electric vehicles and hybrid vehicles. There is a situation.

In particular, the most important thing in lithium ion capacitors is the method of pre-doping lithium. This is because the characteristics, mass productivity, and price competitiveness of the cell are determined by how quickly and uniformly doping is performed.

In the conventional lithium free doping technique, a mesh conductive sheet was used together. The use of the mesh conductive sheet makes it difficult to control the thickness of the electrode by generating slurry fluidity, and it is difficult to manufacture a winding type cell due to insufficient tension of the mesh conductive sheet.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to pre-dope lithium ions in an electrode before the cell is assembled, so that the secondary power electrode can be manufactured in a simple manner while improving the doping rate of the lithium ions. A manufacturing method and a method of manufacturing a secondary power source using the same are provided.

According to one or more exemplary embodiments, a method of manufacturing an electrode for a secondary power source includes: forming an electrode material on a conductive sheet; Depositing lithium on the electrode material to form a lithium thin film layer; Doping the deposited lithium onto the electrode material; And adjusting the doping level by monitoring the doping amount of lithium.

The conductive sheet may be a foil-type conductive sheet.

The depositing step may be performed in a vacuum state.

The doping level may be adjusted to a 0.1 to 0.15 V open-circuit potential (OCP) level.

The doping may be performed by depositing a conductive sheet on which an electrode material is formed in an electrolyte, and depositing lithium into the electrode material.

According to another aspect of the present invention, there is provided a method of manufacturing a stacked lithium ion capacitor, comprising: forming an electrode material on a conductive sheet; Depositing lithium on the electrode material; Doping the deposited lithium onto the electrode material; Monitoring the doping amount of lithium to adjust the doping level to form a first electrode; And sequentially stacking a separator and a second electrode on the first electrode.

According to another embodiment of the present invention, a method of manufacturing a wound lithium ion capacitor includes forming an electrode material on a conductive sheet; Depositing lithium on the electrode material; Doping the deposited lithium onto the electrode material; Monitoring the doping amount of lithium to adjust the doping level to form a first electrode; And sequentially stacking and winding the separator and the second electrode on the first electrode.

According to another embodiment of the present invention, a method of manufacturing a secondary power source includes: forming an electrode material on a conductive sheet; Depositing lithium on the electrode material; Doping the deposited lithium onto the electrode material; Monitoring the doping amount of lithium to adjust the doping level to form a first electrode; And opposing the first electrode and the second electrode with the separator interposed therebetween.

The secondary power source may be a lithium ion battery.

According to the method of manufacturing an electrode for a secondary power source according to an embodiment of the present invention, an optimal doping amount can be adjusted by doping before assembling, and the doping process is simplified. In addition, since lithium is deposited by a vacuum deposition method, it is possible to deposit lithium uniformly, and the doping process is simplified. That is, the speed and uniformity of lithium doping are greatly improved.

1 is a cross-sectional view schematically showing a stacked lithium ion capacitor cell according to an embodiment of the present invention;
2A to 2D are views for explaining a process of manufacturing a cathode of a stacked lithium ion capacitor according to an embodiment of the present invention;
3 is a cross-sectional view schematically showing a wound lithium ion capacitor cell according to an embodiment of the present invention, and
4 is a flowchart illustrating a method of manufacturing a cathode of a lithium ion capacitor according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. In the following detailed description of the preferred embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In addition, the same reference numerals are used throughout the drawings for parts having similar functions and functions.

In addition, throughout the specification, the term 'comprising' an element means that the element may further include other elements, except for the case where there is no contrary description.

Hereinafter, a method of manufacturing a secondary power electrode and a method of manufacturing a secondary power source using the same will be described with reference to FIGS. 1 to 4.

1 is a cross-sectional view schematically showing a stacked lithium ion capacitor cell according to an embodiment of the present invention. As shown in FIG. 1, the stacked lithium ion capacitor cell 101 includes a first electrode 110, a second electrode 120, and a separator 130.

The second electrode 120 (hereinafter, referred to as 'cathode' in one embodiment of the present invention) is formed by applying the cathode electrode material layer 123 to the cathode conductive sheet 121. The cathode electrode material layer 123 may be formed of a material capable of reversibly supporting lithium ions, but is not limited thereto. For example, carbon materials, such as graphite and hard carbon coke, a polyacene type substance (henceforth PAS) etc. can be used.

In addition, a cathode may be formed by mixing the cathode electrode material layer 123 and a conductive material, and the conductive material is not limited thereto, and examples thereof include acetylene black, graphite, and metal powder.

The thickness of the cathode electrode material layer 123 is not particularly limited, but may be, for example, 10 to 100 μm.

The negative electrode conductive sheet 121 may be formed of a metal foil to transmit an electrical signal to the negative electrode material layer 123 and to collect accumulated charges. The metal foil may be made of stainless steel, copper, nickel, titanium, or the like.

As the form of the conductive sheet 121, a porous or non-porous sheet-like metal such as a mesh conductive sheet or a foil conductive sheet is used.

A detailed method of manufacturing the negative electrode will be described later with reference to FIGS. 2A to 2D.

The first electrode 110 (hereinafter, referred to as “anode” in one embodiment of the present invention) is formed by applying the anode electrode material layer 113 to the cathode conductive sheet 111. The cathode electrode material layer 113 may be formed of a material capable of reversibly supporting lithium ions, but is not limited thereto. For example, activated carbon may be used, and the activated carbon, a conductive material, and a binder may be mixed to form a cathode. can do.

The thickness of the anode electrode material is not particularly limited, but may be, for example, 10 to 400 μm.

The positive electrode conductive sheet 111 serves as a conductive sheet that transmits an electrical signal to the negative electrode material layer 113 and collects accumulated charges, and may be made of metal foil like the negative electrode conductive sheet. The metal foil may be made of aluminum, stainless steel, titanium, or the like.

The separator 130 may be made of a porous material to allow ions to pass through. In this case, examples of the porous material include polypropylene, polyethylene, glass fiber, and the like.

One cathode 120, the separator 130, and the anode 110 form a unit cell 100 of a capacitor, and when a plurality of unit cells are stacked, higher capacitance may be obtained.

In the prior art, after stacking a plurality of cathodes 120 and anodes 110, an electrolyte was impregnated to manufacture a capacitor. In this case, in order to dope lithium ions, a separate lithium metal was required for the stacked cells, and a separate current was required to be applied.

Hereinafter, a process of manufacturing a cathode of a lithium ion capacitor will be described with reference to FIGS. 2A to 2D.

2A is a cross-sectional view schematically showing a cathode 1 according to an embodiment of the present invention. The cathode 120 is formed by applying the electrode material layer 113 to the conductive sheet 111.

In an exemplary embodiment of the present invention, even if only a foil conductive sheet is used as the conductive sheet 111, a lithium ion capacitor having a high energy density can be manufactured. The mesh was needed to dope lithium ions after cell assembly. However, in the exemplary embodiment of the present invention, doping of lithium ions is performed in the state of the cathode 120, and since the lithium thin film layer 140 is utilized, no mesh is required. Even without the mesh, lithium ions may be evenly doped to the conductive sheet 111 by the lithium thin film layer 140.

Therefore, since the foil conductive sheet is used, the thickness of the electrode can be easily adjusted, and various types of cells such as a winding type can be easily manufactured.

2B is a cross-sectional view schematically illustrating a step of depositing a lithium thin film layer 140 according to an embodiment of the present invention. In one embodiment of the present invention, after applying the cathode electrode material layer 123 to the conductive sheet 121, Li is deposited to form a lithium thin film layer 140.

In the prior art, in doping with lithium ions, doping is performed only by impregnation with an electrolyte and application of separate electricity. However, since the lithium thin film layer 140 is formed first, since lithium is first deposited thinly on the electrode material layer 123, the lithium ions may be doped only by being impregnated into the electrolyte.

In addition, in the related art, a separate lithium metal layer is required in a stacked cell for lithium ion doping. However, in the exemplary embodiment of the present invention, since the lithium thin film layer 140 is deposited, the process of disposing the lithium metal layer is not necessary. Therefore, it is possible to reduce the dead volume, which is formed due to the conventional lithium metal layer, so that the thickness of the electrode becomes thin, which makes the capacitor small in size.

Furthermore, the amount of lithium metal required for lithium doping can be optimized, and lithium doping can be made uniform over the entire conductive sheet, thereby improving the energy density and cycle characteristics of the capacitor.

Practically the amount needed for the doping of lithium is very small.

Therefore, according to one embodiment of the present invention, lithium may form an appropriate amount of the lithium thin film layer by vacuum deposition.

2C is a cross-sectional view schematically illustrating a doping step of lithium ions according to an embodiment of the present invention.

In the prior art, in the case of lithium ion capacitors, electroplating was used when doping lithium ions. The separator was placed between the negative electrode and the lithium metal, so that the separator was impregnated with the electrolyte solution so as to face each other. In addition, a current was applied between the cathode and the metal to induce doping from the metal to the cathode.

2C illustrates a doping process according to an embodiment of the present invention. The lithium ion is doped into the current collector layer 121 by diffusion by impregnating a cathode in which lithium is deposited. Although the said electrolyte solution is not limited to this, The aprotic organic-solvent electrolyte solution of a lithium salt, etc. are mentioned.

On the other hand, since lithium is thinly deposited, doping of lithium ions may be performed by diffusion without the need for a separate power application process. In addition, since the lithium thin film layer is uniformly deposited, doping of lithium ions can be uniformly performed with respect to the surface area of the entire negative electrode, and the energy density and cycle characteristics can be improved accordingly.

In addition, the doping amount may be optimized by measuring the amount of lithium ions doped in the measuring unit 150. In order to optimize the doping amount, it is desirable to monitor the doping level to be maintained at 0 to 0.15V Open Circuit Potential (OCP) level.

2D is a schematic exploded view illustrating a unit cell 100 of a lithium ion capacitor according to an embodiment of the present invention. In the lithium ion capacitor according to the exemplary embodiment of the present invention, the negative electrode 120, the separator 130, and the positive electrode 110 are stacked to form one unit cell 100. A plurality of unit cells 100 are stacked to form the stacked capacitor cell 101 shown in FIG. 1.

In the prior art, a separate doping process was required by stacking the unit cells 100. However, according to one embodiment of the present invention, since lithium ions are doped in the negative electrode, there is no need to impregnate all of the stacked cells. Therefore, the manufacturing process after laminating | stacking the unit cell 100 becomes very simple.

3 is a schematic cross-sectional view of a wound lithium ion capacitor according to an embodiment of the present invention. The winding-type lithium ion capacitor is formed by winding the unit cell 100 of FIG. 2D. In the case of the embodiment of the present invention, since the foil conductive sheet is used and there is no separate lithium metal layer using the lithium thin film layer, the thickness of the electrode is thin and the shape is free.

4 is a flowchart illustrating a method of manufacturing a cathode of a lithium ion capacitor according to an embodiment of the present invention.

First, the electrode for the secondary power source forms the electrode material layer 123 on the negative electrode conductive sheet 121 (S410). A negative electrode 120 may be prepared by providing a negative electrode material 123 capable of supporting lithium ions and applying a negative electrode material 123 on a mesh conductive sheet or foil conductive sheet in a metal foil form. The conductive sheet may be made of only a foil conductive sheet.

In addition, the lithium thin film layer 140 is deposited on the conductive sheet 121 on which the electrode material is formed (S420). A lithium thin film layer is deposited for lithium doping by diffusion. Vacuum deposition is used for thin and uniform deposition. Then, the conductive sheet 121 is to be evenly deposited lithium.

After depositing the lithium thin film layer 140 (S420), doped with lithium ions on the cathode electrode material (S430). In order to dope the lithium ions, the electrolyte is impregnated to diffuse the lithium ions from the lithium thin film layer 140 to the conductive sheet 121 to dope the cathode. Unlike the doping method by the conventional electroplating method, according to one embodiment of the present invention doping is made by precipitating the cathode in the electrolyte without applying a separate current.

During doping of the lithium ions (S430), the doping is monitored to adjust the doping level (S440). The doping level is monitored to achieve the desired amount of doping. Then, the doping time is adjusted to achieve the desired amount of doping level. The doping level can be adjusted to a 0 to 0.15V open-circuit potential (OCP) level.

The conductive sheet may be a foil conductive sheet. The use of the foil conductive sheet makes the slurry not fluid and facilitates electrode thickness control. And the tension of the slurry facilitates the manufacture of the wound cell.

Meanwhile, the anode 110 having the anode electrode material 113 coated on the conductive sheet 111 is prepared, and the separator 130 is prepared. The cathode 120, the separator 130, and the anode 110 are stacked to form a cell, and the cells are stacked or wound to form a stacked capacitor cell or a wound capacitor cell.

As described above, the lithium ion capacitor manufactured according to the method for manufacturing a secondary power source of the present invention does not use a mesh conductive sheet, so that a free form cell such as a winding type can be manufactured, and a dead volume volume) and the optimization of lithium doping can improve energy density and cycle characteristics. In addition, since the step of inserting the lithium foil can be eliminated, the cell structure becomes stable and simple.

Meanwhile, although the secondary power source according to an embodiment of the present invention is assumed to be a lithium ion capacitor, this is only an embodiment and the technical idea of the present invention may be applied to other secondary power sources. For example, the secondary power source may be, for example, a lithium ion battery.

According to another embodiment of the present invention, a lithium ion battery may be manufactured by applying the electrode manufacturing method. The lithium ion battery is formed by opposing the first electrode and the second electrode with the separator interposed therebetween. In the prior art, the pre-doping process was not utilized because the lithium pre-doping process is different from the actual manufacturing process. However, the lithium free doping technique of an embodiment of the present invention may be applied as an additional process to the LiB manufacturing process, and may improve cathode performance. The lithium free doping technology can prevent the loss of Li by preventing the formation of an initial solid electrolyte interface (SEI) on the negative electrode material, and maximize the use of LiB output characteristics by maximizing the use of a large specific surface area of the negative electrode. Can be.

Claims (9)

Forming an electrode material over the conductive sheet;
Depositing lithium on the electrode material by vacuum deposition to form a lithium thin film layer;
Doping the deposited lithium onto the electrode material; And
Monitoring the doping amount of the lithium to adjust the doping level;
The method of claim 2, wherein the doping comprises depositing the conductive sheet on which the electrode material is formed in an electrolyte, and performing lithium deposition by infiltrating the electrode material.
The method of claim 1,
The conductive sheet is a foil-type conductive sheet electrode manufacturing method for a secondary power supply.
delete The method of claim 1,
The doping level is,
A method for manufacturing electrodes for secondary power sources controlled at 0.1 to 0.15 V open-circuit potential (OCP) levels.
delete Forming an electrode material over the conductive sheet;
Depositing lithium on the electrode material;
Doping the deposited lithium onto the electrode material;
Monitoring the doping amount of the lithium to adjust the doping level to form a first electrode; And
Sequentially stacking a separator and a second electrode on the first electrode;
The method of claim 1, wherein the doping comprises depositing the conductive sheet on which the electrode material is formed in an electrolyte, and performing deposition of the deposited lithium into the electrode material.
Forming an electrode material over the conductive sheet;
Depositing lithium on the electrode material;
Doping the deposited lithium onto the electrode material;
Monitoring the doping amount of the lithium to adjust the doping level to form a first electrode; And
Sequentially stacking and winding a separator and a second electrode on the first electrode;
The method of claim 1, wherein the doping comprises depositing the conductive sheet on which the electrode material is formed in an electrolyte solution, and performing deposition of the deposited lithium into the electrode material.
Forming an electrode material over the conductive sheet;
Depositing lithium on the electrode material;
Doping the deposited lithium onto the electrode material;
Monitoring the doping amount of the lithium to adjust the doping level to form a first electrode; And
And opposing the first electrode and the second electrode with a separator interposed therebetween, wherein the doping comprises depositing a conductive sheet on which the electrode material is formed in an electrolyte solution, and the deposited lithium penetrates into the electrode material. Secondary power manufacturing method performed by.
The method of claim 8,
The secondary power source,
A method of manufacturing a secondary power source that is a lithium ion battery.

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